/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.server.ai;

import javax.xml.stream.XMLStreamException;

import java.util.Comparator;

import net.sf.freecol.common.io.FreeColXMLReader;
import net.sf.freecol.common.io.FreeColXMLWriter;
import net.sf.freecol.common.model.FreeColObject;

import org.w3c.dom.Element;


/**
 * Abstract class of AI object with a simple enclosed comparable
 * integer value.
 */
public abstract class ValuedAIObject extends AIObject
{

    /** A comparator by descending AI object value. */
    public static final Comparator< ValuedAIObject > valuedComparator
            = Comparator.comparingInt( ValuedAIObject::getValue ).reversed( );

    /** The value of this AIObject. */
    private int value;


    /**
     * Creates a new <code>ValuedAIObject</code> instance.
     *
     * @param aiMain an <code>AIMain</code> value
     */
    public ValuedAIObject( AIMain aiMain )
    {
        super( aiMain );
    }

    /**
     * Creates a new uninitialized <code>ValuedAIObject</code> instance.
     *
     * @param aiMain an <code>AIMain</code> value
     * @param id The object identifier.
     */
    public ValuedAIObject( AIMain aiMain, String id )
    {
        super( aiMain, id );

        this.value = 0;
    }

    /**
     * Creates a new <code>ValuedAIObject</code> from the given
     * XML-representation.
     *
     * @param aiMain The main AI-object.
     * @param element The root element for the XML-representation 
     *     of the object.
     */
    public ValuedAIObject( AIMain aiMain, Element element )
    {
        super( aiMain, element );
    }

    /**
     * Creates a new <code>ValuedAIObject</code> from the given
     * XML-representation.
     *
     * @param aiMain The main AI-object.
     * @param xr The input stream containing the XML.
     * @throws XMLStreamException if a problem was encountered
     *      during parsing.
     */
    public ValuedAIObject( AIMain aiMain,
                           FreeColXMLReader xr ) throws XMLStreamException
    {
        super( aiMain, xr );
    }


    /**
     * Get the <code>Value</code> value.
     *
     * @return an <code>int</code> value
     */
    public final int getValue( )
    {
        return value;
    }

    /**
     * Set the <code>Value</code> value.
     *
     * @param newValue The new Value value.
     */
    public final void setValue( final int newValue )
    {
        this.value = newValue;
    }


    // Override FreeColObject

    /**
     * {@inheritDoc}
     */
    @Override
    public int compareTo( FreeColObject other )
    {
        int cmp = 0;
        if ( other instanceof ValuedAIObject )
        {
            ValuedAIObject vao = ( ValuedAIObject ) other;
            cmp = vao.value - this.value;
        }
        if ( cmp == 0 ) cmp = super.compareTo( other );
        return cmp;
    }


    // Serialization

    /**
     * {@inheritDoc}
     */
    @Override
    protected void writeAttributes( FreeColXMLWriter xw ) throws XMLStreamException
    {
        super.writeAttributes( xw );

        xw.writeAttribute( VALUE_TAG, value );
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void readAttributes( FreeColXMLReader xr ) throws XMLStreamException
    {
        super.readAttributes( xr );

        setValue( xr.getAttribute( VALUE_TAG, - 1 ) );
    }
}
